diff --git a/README.md b/README.md
index c284dcb..f8dc319 100644
--- a/README.md
+++ b/README.md
@@ -115,7 +115,7 @@ CACHE_MAX_AGE 3560d
 You can override these at run time by adding the following to your docker run command.  They accept the standard nginx notation for sizes (m) and durations (m/h/d).
 
 ```
--e CACHE_MEM_SIZE=4000m -e CACHE_DISK_SIZE=1000g -e CACHE_MAX_AGE 3560d
+-e CACHE_MEM_SIZE=4000m -e CACHE_DISK_SIZE=1000g -e CACHE_MAX_AGE=3560d
 ```
 
 CACHE_MEM_SIZE relates to the memory allocated to NGINX for the cache manager process.  1 megabyte will hold around 8000 cache entries, and for Monolithic slicing in 1MB slices, this means each 1M allocated will service around 8GB on disk.  The default size of 500MB should allow you to have a cache of up to 4TB quite comfortably.  Any other available memory in your cachebox should then be used for the Filesystem cache.